The competitive ratio for quantifying competition between component crops in cereal based intercropping system

Investigations carried out at the Regional Research Station, Aruppukottai, Tamil Nadu, India during 1994-'95, 1995-'96 and 1996-'97 revealed that grain yield from sole cropping was higher than from intercropping. The competitive ratio (CR) of main crop increased and intercrop decreased irrespective of cropping systems in the first two years of study. In sorghum + cowpea system the CR value of sorghum was more than unity (1.01 to 1.34) and cowpea was less than unity (0.74 to 0.99) in all the three years of study. In sorghum + pearlmillet system the CR value of sorghum was more than unity (1.28 to 1.50) during first two years and less than unity during third year with application of fertilizers. However, the CR value of intercropped pearlmillet during less rainfall year was more than unity (1.03 to 1.22). In maize + cowpea system, the CR value of maize was more than unity (1.05 to 1.18) during first two years and the CR value of intercropped cowpea was higher at increased levels of fertilizer application.